Norway to America-1867

I don't have much information to go on but perhaps somebody can lead me in the right direction. My family came from Alta, Finnmark, Norway in 1867 to live in Wisconsin. I believe I found my gg-grandfather's record of naturalization. The date and port of arrival is July, 1867-Detroit, MI. Is there a way to find out the most likely port of departure or perhaps the names of ships arriving in Detroit in 1867? I'd appreciate any ideas. Thanks, Kelly